export class Queue<T> {
  private data: T[] = [];
  push(item: T) {
    return this.data.push(item);
  }
  pop(): T | undefined {
    if (this.data.length != 0) {
      return this.data.shift();
    }
    return;
  }
}

const obj = new Queue<number>();
obj.push(6);
